Fluid-Based Topology Optimization of an EGR Flowsplitter

In order to meet the required Exhaust Gas Recirculation rate, EGR modules contain nowadays heat exchangers. Typically, single-pass or two-pass coolers are used. When an EGR cooler with a two-pass inlet is considered, a mass flow split ratio of 0.5 per duct is a required condition for obtaining a maximum cooler efficiency. The needed partition of the exhaust flow upstream of the cooler is achieved by using flowsplitter geometries.

This presentation deals with the optimization of a flowsplitter. The objective of the study was to obtain a design with an improved flow balance. Furthermore, a reduction of the total pressure loss inside the flowsplitter should be realized.

The fluid optimization was conducted with the topology optimizer Tosca Fluid. In contrary to traditional parametric approaches, where a CFD run is needed after each design modification, a topology optimization acts as a co-simulation and is finished after a single coupled run. In order to provide a high flexibility for the design optimization, the initial geometry represents the available design space. To account for manufacturing constraints and further geometric aspects, the design proposal is reconstructed with a CAD tool afterwards.

A CFD run based on the reconstructed design proposal revealed a significant improved mass flow balance and an impressive reduction of the total pressure loss.